Yaskawa GA800 A.134 Fault — What It Means
The A.134 code displayed on a Yaskawa GA800 VFD does not appear in the standard alphanumeric fault lists published in GA800 manuals. Yaskawa GA800 documentation typically uses fault codes like oC, ov, or CPF06, so A.134 may be a custom alarm, a display artifact, or specific to a particular firmware revision or option card installed on your drive. The exact meaning must be verified from the alarm history menu on the keypad or from the specific manual revision for your installed hardware.
Because the code is not manufacturer-verified in available documentation, troubleshooting follows the general Yaskawa pattern for unrecognized or option-related alarms: power down the drive, inspect and reseat all option cards and communication modules, check for loose connections on control terminals, then power back up. If the fault reappears, consult the detailed alarm table in your drive’s installation manual or contact Yaskawa technical support with the full alarm text and your drive’s firmware version.
Before You Replace Anything
Technicians sometimes replace the entire VFD when the fault is actually a loose or incompatible option card. Before ordering a new drive, de-energize the unit and reseat every option card and communication module, then clear the fault history and power cycle.
Common Causes
- Option card not seated or incompatible: (~35%) A communication or I/O option card may be loose in its connector or running firmware that does not match the drive, generating an unrecognized alarm code.
- Control board fault or memory corruption: (~25%) The drive’s internal control board may have experienced a transient error or parameter corruption that displays a non-standard code.
- Firmware or parameter mismatch: (~20%) A recent firmware update or parameter restore may have introduced an alarm identifier not documented in older manuals.
- Display or keypad communication error: (~10%) The keypad or remote operator interface may be misreading the alarm buffer and showing a garbled code.
- Grounding or noise on control wiring: (~10%) Electrical noise or a ground fault in the control circuit can corrupt the alarm register and produce unexpected codes.
Quick Diagnosis
Answer these to narrow it down fast.
Does the alarm history menu show additional text or a different code alongside A.134?
No: The code may be a display artifact or firmware-specific identifier. Proceed to power down, reseat all option cards, and clear the alarm history before re-energizing the drive.
Do you have any communication or I/O option cards installed in the drive?
No: The fault is likely internal to the control board or a parameter-memory issue. Try a full power cycle and parameter initialization, then contact Yaskawa support if the code persists.
Does the drive run normally and only log A.134 as a history event, or does it refuse to start?
No: If the drive is tripped and locked out, the fault is active. Follow the full troubleshooting sequence below to isolate the cause before the drive will reset.
Step-by-Step Fix
- Write down the full alarm text from the keypad alarm-history menu (usually parameter H1 or the alarm log screen) and note your drive’s firmware version from the monitor menu.
- De-energize the drive by opening the main disconnect and waiting at least five minutes for DC bus capacitors to discharge before touching any internal components.
- Remove and reseat every option card and communication module, ensuring each card locks firmly into its backplane connector and that no pins are bent or corroded.
- Inspect control-terminal wiring for loose screws, damaged insulation, or signs of arcing on terminals TB1 through TB5, and verify that the control-power jumper is correctly installed per the wiring diagram.
- Restore power and clear the alarm by pressing the RESET key on the keypad or cycling the FWD/REV input, then observe whether A.134 reappears immediately or after the drive starts.
- Consult the alarm table in your GA800 installation manual or technical-data sheet using the full alarm text from step 1, and follow the manufacturer’s prescribed remedy for that specific fault.
- Contact Yaskawa technical support with the alarm code, firmware version, and installed option cards if the fault persists after reseating and power cycling, as A.134 may require a firmware update or control-board replacement.
Parts Often Needed
| Part | Notes |
|---|---|
| Yaskawa GA800 option card (communication or I/O module) | Amazon | Match the card type and catalog number to your existing module if reseating does not resolve the fault. |
| Yaskawa GA800 control board | Amazon | Required if the drive displays A.134 after all option cards are removed and the fault is determined to be an internal board failure. |
When to Call a Pro
Call a qualified VFD technician or an authorized Yaskawa service center whenever A.134 persists after reseating option cards and power cycling, when you lack the GA800 manual revision that documents the code, or when the drive must remain in service and you cannot afford extended downtime for trial-and-error troubleshooting. Professional support is also required if the fault is accompanied by smoke, burning odors, or visible component damage on the control board. High-voltage DC bus work and control-board replacement should always be performed by trained personnel with proper lockout/tagout procedures and insulated tools.
Rough cost: A pro service call runs about $200–600.